JP2010087205A - Multi-junction thin-film photoelectric converter - Google Patents

Abstract

A multi-junction photoelectric conversion device having high conversion efficiency and having a high open-circuit voltage by balancing a short-circuit current value at a high value by connecting silicon-based and CIS-based thin-film photoelectric conversion units in series.
A multi-junction thin film photoelectric conversion device includes silicon thin film photoelectric conversion units (3, 5) and a CIS thin film photoelectric conversion unit (7), which are connected in series via intermediate layers (4, 6). The silicon-based thin film photoelectric conversion device is capable of photoelectric conversion of near-infrared light of 1100 nm or more, which is difficult to perform photoelectric conversion, and can use a wide range of solar spectrum. A conversion device can be provided.
[Selection] Figure 1

Description

  The present invention relates to a multi-junction thin-film photoelectric conversion device including a silicon-based and CIS-based thin-film photoelectric conversion unit and connected in series via an intermediate layer.

  In recent years, photoelectric conversion devices that convert light into electricity using photoelectric effects inside semiconductors have attracted attention and are being developed vigorously. Among these photoelectric conversion devices, silicon-based thin film photoelectric conversion devices are at low temperatures. Since it can be formed on a large area glass substrate or stainless steel substrate, cost reduction can be expected. In addition, a CIS-based thin film photoelectric conversion device has been developed that uses a thin film having a chalcopyrite structure composed of Cu, In, Se, etc., which is inexpensive and has very little deterioration due to light or radiation, as a light absorption layer. (See Patent Document 1). Patent Document 1 discloses a method for producing a CIS-based thin film solar cell. In order to form a CIS-based thin film photoelectric conversion device, a temperature atmosphere of 500 to 600 ° C. is required.

  Silicon-based thin-film photoelectric conversion devices have been developed for the purpose of increasing efficiency, such as hybridization and introduction of an intermediate layer, but only visible light to near-infrared light of about 1100 nm can be used for photoelectric conversion. On the other hand, CIS-based thin film photoelectric conversion devices are capable of photoelectric conversion of near-infrared light from 1100 to 1300 nm, which is not possible with silicon-based thin film photoelectric conversion devices as well as visible light, and widely use the sunlight spectrum. In recent years, development has been carried out vigorously because it is possible to do so.

  As a method for improving the conversion efficiency of a photoelectric conversion device, a photoelectric conversion device employing a structure called a multi-junction type in which two or more photoelectric conversion units are stacked is known.

  In this method, a photoelectric conversion unit including a photoelectric conversion layer including a photoelectric conversion layer having a large optical forbidden bandwidth is disposed on the light incident side of the photoelectric conversion device, and a photoelectric conversion layer including a photoelectric conversion layer having a small band gap in order behind the photoelectric conversion layer. By arranging one or more of these, photoelectric conversion over a wide wavelength range of incident light is possible, and conversion efficiency of the entire apparatus is improved by effectively using incident light.

In the present application, the photoelectric conversion unit disposed relatively on the light incident side is referred to as a front photoelectric conversion unit, and the photoelectric conversion unit disposed adjacent to the side farther from the light incident side than this is rear photoelectric conversion. Called a unit.

In a photoelectric conversion device in which three or more photoelectric conversion units are stacked, a rear photoelectric conversion unit arranged second or later from the light incident side is a front photoelectric conversion unit, and is adjacent to a side relatively far from the light incident side. Thus, there are a plurality of rear photoelectric conversion units arranged.

  In the present application, in order to provide photoelectric conversion of light having a wavelength that could not be absorbed by the silicon thin film solar cell disposed on the light incident side, the CIS thin film solar cell is located far from the light incident side with respect to the silicon thin film solar cell. It is a multi-junction thin-film photoelectric conversion device in which a battery is arranged.

  Incident light can be used effectively by adopting the above multi-junction structure, but the characteristics of the entire multi-junction photoelectric conversion device, especially the short-circuit current density, is the shorter of the short-circuit current densities of the stacked photoelectric conversion units. Limited to current density. Therefore, in order to improve the characteristics of the entire multi-junction photoelectric conversion device, it is necessary to balance the short-circuit current density generated in each photoelectric conversion unit.

  Therefore, in recent years, a stacked photoelectric conversion device having a structure in which both a light transmitting property and a light reflecting property are interposed between a plurality of stacked photoelectric conversion units and a conductive intermediate layer is interposed has been proposed. . In this case, a part of the light reaching the intermediate layer is reflected, the amount of light absorption in the front photoelectric conversion unit located on the light incident side of the intermediate layer is increased, and the current value generated in the front photoelectric conversion unit Can be increased. For example, a multi-junction thin film photoelectric conversion device having an amorphous silicon photoelectric conversion unit and a crystalline silicon photoelectric conversion unit can reflect transmitted light between the amorphous silicon photoelectric conversion unit and the crystalline silicon photoelectric conversion unit. In the case where an intermediate layer having a thickness is inserted, the current generated by the amorphous silicon photoelectric conversion unit can be increased without increasing the film thickness of the amorphous silicon layer.

  Alternatively, the amorphous silicon photoelectric conversion unit due to photodegradation that becomes conspicuous as the thickness of the amorphous silicon layer increases because the thickness of the amorphous silicon layer necessary to obtain the same current value can be reduced. It is possible to suppress the deterioration of characteristics. As such an intermediate layer, it is preferable that the wavelength region of light absorbed by the front photoelectric conversion unit is selectively reflected and the wavelength region of light absorbed by the rear photoelectric conversion unit is selectively transmitted, Research and development is actively conducted.

However, in a silicon-based thin film photoelectric conversion device, a silicon-based thin film photoelectric conversion device using a silicon-based material such as amorphous silicon, amorphous silicon germane, or microcrystalline silicon has a photosensitivity only up to ˜1100 nm, and an intermediate layer Even if the light is selectively reflected and selectively transmitted using the light, the light having no photosensitivity is lost as it is, and the silicon-based thin film photoelectric conversion device that has not been effectively utilized is once heated to 250 ° C. or higher. Even if it returns, it will stop functioning as a photoelectric conversion device. For this reason, there is a problem in connecting the silicon thin film photoelectric conversion unit and the CIS thin film photoelectric conversion unit in series.
JP 2006-165386 A

  By connecting a CIS-based thin film photoelectric conversion unit in series with a silicon-based thin film photoelectric conversion unit, it is possible not only to photoelectrically convert a wide sunlight spectrum, including near-infrared light, which was impossible with a silicon-based multi-junction thin film photoelectric conversion device. Thus, it is possible to manufacture a multi-junction thin film photoelectric conversion device having a high open-circuit voltage that cannot be achieved only by the CIS thin film photoelectric conversion unit.

According to the present invention, it is possible to photoelectrically convert a wider sunlight spectrum than before, and it is possible to provide a multi-junction thin film photoelectric conversion device with high photoelectric conversion efficiency in which the generated short-circuit current density is balanced at a high value. Become.

The multi-junction thin film photoelectric conversion device according to the present invention has the following configuration.


1). A multi-junction thin-film photoelectric conversion device comprising a silicon-based and CIS-based thin film photoelectric conversion unit, wherein the silicon-based photoelectric conversion unit and the CIS-based thin film photoelectric conversion unit are connected in series via an intermediate layer.

  2). The multi-junction thin-film photoelectric conversion device according to 1), wherein the silicon-based thin-film photoelectric conversion unit is composed of one or more members selected from the group consisting of amorphous silicon, amorphous silicon germane, and microcrystalline silicon. .

  3). The multi-junction thin-film photoelectric conversion device according to any one of 1) or 2), wherein the CIS-based thin film photoelectric conversion unit is formed from CIS-based nanoparticles.

  4). The CIS-based thin film photoelectric conversion unit has a buffer layer, and the buffer layer is composed of at least one of the group consisting of ZnO, ZnS, and CdS. Multi-junction thin film photoelectric conversion device.

  5). The intermediate layer includes at least one layer laminated in the order of transparent oxide layer / carbon layer / transparent oxide layer, and the multi-junction thin-film photoelectric conversion device according to any one of 1) to 4), Conversion device.

  6). The multi-junction thin film photoelectric conversion device according to 5), wherein the transparent oxide layer constituting the intermediate layer is formed of zinc oxide.

  7). The multi-junction thin-film photoelectric converter according to any one of 1) to 6), wherein an intermediate layer provided between the silicon-based thin-film photoelectric conversion unit and the CIS-based thin-film photoelectric conversion unit is formed of zinc oxide. Conversion device.

  8). The multi-junction thin-film photoelectric conversion device according to any one of 1) to 7), wherein the intermediate layer has a thickness of 10 to 2000 mm.

  9). The multi-junction thin-film photoelectric conversion device according to any one of 5) to 8), wherein the transparent oxide layer constituting the intermediate layer is formed of conductive oxygenated silicon.

  10). A back electrode is provided on the side opposite to the light incident side of the multi-junction thin film photoelectric conversion device, and the transparent oxide semiconductor layer used for the back electrode layer is one of the group consisting of boron, aluminum, and germanium. The multi-junction thin film photoelectric conversion device according to any one of 1) to 9), wherein the above element is doped.

  11). The method for producing a multi-junction thin film photoelectric conversion device according to any one of 1) to 9), wherein the CIS thin film photoelectric conversion unit is produced in a temperature range of 200 ° C. or less.

  According to the present invention, a CIS-based thin film photoelectric conversion unit having photosensitivity also in the infrared region of 1100-1300 nm is connected in series to a silicon-based thin film photoelectric conversion unit, so that a wider sunlight spectrum can be photoelectrically converted than before, It becomes possible to manufacture a multi-junction thin-film photoelectric conversion device having a high open-circuit voltage that cannot be achieved only by the CIS-based thin-film photoelectric conversion unit.

  Due to the above effects, the present invention can provide a high-performance multi-junction thin film photoelectric conversion device.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each drawing of the present application, dimensional relationships such as thickness and length are appropriately changed for clarity and simplification of the drawings, and do not represent actual dimensional relationships. Moreover, in each figure, the same referential mark represents the same part or an equivalent part.

  FIG. 1 shows a cross-sectional view of a silicon-based and CIS-based multi-junction thin film photoelectric conversion device according to an example of an embodiment of the present invention.

  On the transparent substrate 1, the transparent electrode layer 2, the front silicon photoelectric conversion unit 3, the intermediate layer 4, the rear silicon photoelectric conversion unit 5, the intermediate layer 6, the CIS photoelectric conversion unit 7, and the back electrode layer 8 are arranged in this order. Has been. In FIG. 1, the silicon-based photoelectric conversion unit is composed of two parts, a front photoelectric conversion unit and a rear photoelectric conversion unit. However, the present invention is also applied to a case where three or more silicon-based photoelectric conversion units are stacked. be able to.

  For example, in the three-junction silicon-based photoelectric conversion device arranged in the order of the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit from the light incident side, the first photoelectric conversion unit and the second photoelectric conversion unit are Each may be regarded as a front photoelectric conversion unit and a rear photoelectric conversion unit, and an intermediate layer may be provided at the boundary between them.

  Alternatively, the second photoelectric conversion unit and the third photoelectric conversion unit may be regarded as a front photoelectric conversion unit and a rear photoelectric conversion unit, respectively, and an intermediate layer may be provided at the boundary between them. Of course, an intermediate layer may be provided on both the boundary between the first photoelectric conversion unit and the second photoelectric conversion unit and on the boundary between the second photoelectric conversion unit and the third photoelectric conversion unit. Examples of the silicon photoelectric conversion device include an amorphous silicon photoelectric conversion unit for the first photoelectric conversion unit, an amorphous silicon germanium or crystalline silicon photoelectric conversion unit for the second photoelectric conversion unit, and a third photoelectric conversion unit. A case where an amorphous silicon germanium or a crystalline silicon-based photoelectric conversion unit is applied may be mentioned, but the combination is not limited thereto.

  An intermediate layer is disposed at the boundary between the silicon-based thin film photoelectric conversion device and the CIS-based thin film photoelectric conversion device. By providing the intermediate layer, it is possible to prevent transmission / diffusion of atoms such as Cu, In, S, Se, and Ga to the silicon thin film photoelectric conversion device side when forming the CIS thin film photoelectric conversion device. I can do it. As the intermediate layer, for example, non-doped ZnO can be used.

A plate-like member or a sheet-like member made of glass, transparent resin, or the like is used for the transparent substrate 1 used in a photoelectric conversion device of a type in which light enters from the substrate side. The transparent electrode layer 2 is preferably made of a conductive metal oxide such as SnO ₂ or ZnO, and is preferably formed using a method such as CVD, sputtering, or vapor deposition. It is preferable that the transparent electrode layer 2 has fine irregularities on the surface because an effect of increasing the scattering of incident light occurs.

As the back electrode layer 8, at least one metal layer made of at least one material selected from Mo, Al, Ag, Au, Cu, Pt, and Cr can be formed by sputtering or vapor deposition. Of these, Mo is preferable. Between the photoelectric conversion unit and the back electrode, ITO, may be formed a layer made of SnO _2, conductive oxides such as ZnO (not shown).

  A plurality of photoelectric conversion units are arranged behind the transparent electrode layer 2 when viewed from the light incident side. In the case of a structure in which two photoelectric conversion units are stacked as shown in FIG. 2, the front photoelectric conversion unit 3 disposed on the light incident side has a relatively wide bandgap material, for example, an amorphous silicon material. A conversion unit or the like is used. The rear photoelectric conversion unit 5 arranged on the rear side includes a material having a relatively narrow band gap, for example, a photoelectric conversion unit made of a silicon-based material containing a crystalline material, an amorphous silicon germanium photoelectric conversion unit, or the like. Used.

  Each silicon-based photoelectric conversion unit is preferably configured by a pin junction including a p-type layer, an i-type layer that is a substantially intrinsic photoelectric conversion layer, and an n-type layer. Among these, those using amorphous silicon for the i-type layer are called amorphous silicon photoelectric conversion units, and those using crystalline silicon are called crystalline silicon photoelectric conversion units. Note that the amorphous or crystalline silicon-based material is not only a case where only silicon is used as a main element constituting a semiconductor, but also an alloy material including elements such as carbon, oxygen, nitrogen, and germanium. Good. The main constituent material of the conductive layer is not necessarily the same as that of the i-type layer. For example, amorphous silicon carbide can be used for the p-type layer of the amorphous silicon photoelectric conversion unit, and n A silicon layer (also referred to as μc-Si) containing crystal in the mold layer can also be used.

  The CIS-based thin film photoelectric conversion unit generally includes a first electrode, a semiconductor thin film photoelectric conversion unit, and a second electrode, the surfaces of which are sequentially stacked on an insulating substrate. Here, the CIS photoelectric conversion unit is generally laminated in the order of a p-type layer, a buffer layer, and an n-type layer, and the photoelectric conversion layer of the p-type layer that occupies the main part is composed of Cu, In, and Se. Things can be used.

  It is preferable to use CdS, ZnS, ZnO or the like for the buffer layer. Moreover, it is preferable that the formation temperature of a p-type layer is 250 degrees or less. In order to form at a low temperature of 250 degrees or less, compound semiconductor nanoparticles containing Cu, In, Se and the like are prepared and applied, and then heat-treated at 200 degrees or less to form a p-type layer of a CIS-based thin film photoelectric conversion device. May be formed.

  In the present invention, between the front photoelectric conversion unit and the rear photoelectric conversion unit, the reflectance for light in the wavelength region that can be absorbed by the front photoelectric conversion unit is high, and the reflectance for light in the wavelength region that cannot be absorbed by the front photoelectric conversion unit is low. An intermediate layer having such reflection characteristics is used.

  The intermediate layer used in the present invention preferably has a transparent oxide layer. As the transparent oxide layer, tin oxide, zinc oxide, ITO, a conductive oxygenated silicon layer, or the like can be used.

  The structure of the intermediate layer having a transparent oxide layer may be, for example, a layer in which transparent oxide layer / carbon layer / transparent oxide layer are laminated in this order in addition to the transparent oxide layer. A plurality of these layers may be used.

The method for forming the transparent oxide layer is not particularly limited as long as it is a means for forming a uniform thin film. For example, in addition to PVD methods such as sputtering and vapor deposition and chemical vapor deposition methods such as various CVD methods, a solution containing a raw material for the transparent oxide layer is applied by spin coating, roll coating, spray coating, dipping coating, etc. There is also a method of forming a transparent oxide layer by heat treatment after coating. For example, conductive oxygenated silicon is produced by additionally introducing CO ₂ gas into the chamber under the same conditions as those for producing the n-type μc-Si layer constituting the photoelectric conversion unit by the plasma CVD method. Is possible and process advantageous.

  Also, the carbon layer has a lower refractive index than the transparent oxide layer, and if the carbon layer formation method is also created by plasma CVD, the photoelectric conversion unit and intermediate layer can be created by one plasma CVD. Therefore, productivity is improved. The film thickness of these transparent oxide layers is preferably from 10 to 2000 mm. When the thickness of the transparent oxide layer is thin, the conductivity of the transparent oxide layer is extremely low, which becomes an obstacle in series connection with the photoelectric conversion unit. Moreover, when the film thickness of a transparent oxide layer is thick, transparency may worsen and production cost may also become high. The refractive index of the carbon layer is preferably 1.2 to 1.9 at a wavelength of 550 nm.

The conductive oxygenated silicon is manufactured by additionally introducing CO ₂ gas into the chamber under the same conditions as those for manufacturing the n-type μc-Si layer constituting the photoelectric conversion unit by the plasma CVD method. Is possible and advantageous in terms of process.

  In the following, as an example of a manufacturing method of a multi-junction thin film photoelectric conversion device having a structure in which a silicon thin film photoelectric conversion unit and a CIS thin film photoelectric conversion unit corresponding to the above-described embodiment are stacked in series, A multi-junction thin film photoelectric conversion device in which CIS thin film photoelectric conversion units are connected in series using compound semiconductor nanoparticles to a silicon thin film photoelectric conversion unit in which a crystalline silicon photoelectric conversion unit and a crystalline silicon photoelectric conversion unit are stacked. This will be described in detail in comparison with a comparative example. In the drawings, the same members are denoted by the same reference numerals, and redundant description is omitted. Moreover, this invention is not limited to a following example, unless the meaning is exceeded.

Example 1
A multi-junction thin film photoelectric conversion device according to FIG. 1 was prepared. Glass was used for the transparent substrate 1 and SnO ₂ was used for the transparent electrode layer 2. The film thickness of the transparent electrode layer 2 at this time was 800 nm, the sheet resistance was 10 ohm / □, and the haze ratio was 15 to 20%. On top of this, a boron-doped p-type silicon carbide (SiC) layer has a thickness of 10 nm, a non-doped amorphous silicon photoelectric conversion layer has a thickness of 200 nm, and a phosphorus-doped n-type μc-Si layer has a thickness of 20 nm. Filmed. Thereby, the amorphous silicon photoelectric conversion unit 3 of the pin junction which is a front photoelectric conversion unit was formed.

  Further, an intermediate layer 4 was formed on the amorphous silicon photoelectric conversion unit 3. First, after the substrate on which the amorphous silicon photoelectric conversion unit 3 is formed is taken out from the plasma CVD apparatus to the atmosphere, it is put into a film forming chamber of a sputtering apparatus for forming a transparent oxide layer 4 made of zinc oxide by sputtering. did. In the case where 2 wt% Al is added to zinc oxide as a sputtering target, Ar gas is introduced as a sputtering gas, the substrate is heated to 150 ° C., the pressure is set to 0.27 Pa, and then zinc oxide is added by DC sputtering. The film was formed with a thickness of 600 mm. The refractive index of zinc oxide was 1.9 (wavelength 550 nm).

  Further, the substrate on which the intermediate layer 4 was formed was taken out from the film forming chamber into the atmosphere and put into a plasma CVD apparatus. On the intermediate layer 4, a boron-doped p-type microcrystalline silicon layer having a thickness of 15 nm, a non-doped crystalline silicon photoelectric conversion layer having a thickness of 2.5 μm, and a phosphorus-doped n-type microcrystalline silicon layer having a thickness of 20 nm are formed by plasma CVD. To form a film. Thereby, the crystalline silicon photoelectric conversion unit 5 of the pin junction which is a back photoelectric conversion unit was formed.

  Further, a non-doped ZnO film having a thickness of 80 nm was formed as an intermediate layer 6 on the rear photoelectric conversion unit 5 by a DC sputtering method. The refractive index of the non-doped ZnO film was 1.85 (wavelength 550 nm). The substrate was taken out into the atmosphere.

A CIS-based thin film photoelectric conversion unit was formed as follows. Add pyridine to CuI and InI ₃ in an Ar atmosphere and stir at room temperature for 1 hour, then add Na ₂ Se methanol solution, cool with dry ice, and stir for 24 hours (until red-brown to black suspension ) Centrifuge for 20 minutes to separate CIS and NaI, add dry methanol to remove pyridine, and apply purified CIS suspended in methanol on the intermediate layer 6 taken out to the atmosphere. After that, the p-layer 7a of the CIS-based thin film photoelectric conversion unit made of CIS was formed by firing in an infrared gold furnace at 200 ° C. for 5 hours while blowing hydrogen selenide.

  Subsequently, it was put into a film forming chamber of a sputtering apparatus for forming a back electrode layer 8 made of zinc oxide 7b and Mo by sputtering. In the case where 2 wt% Al is added to zinc oxide as a sputtering target, Ar gas is introduced as a sputtering gas, the substrate is heated to 150 ° C., the pressure is set to 0.27 Pa, and then zinc oxide is added by DC sputtering. The film was formed with a thickness of 600 mm. Next, Mo was sputtered to form a film with a thickness of 1 micron.

When the photoelectric conversion unit having a light receiving area of 1 cm square was separated from the amorphous silicon solar cell obtained as described above and the spectral sensitivity characteristics were measured, the result shown in FIG. 1 was obtained. The graph shows the standard value when the maximum sensitivity value is 1 in the result of Comparative Example 1 described later. The spectral sensitivity current was calculated from these sensitivity spectra and found to be 16.5 mA / cm ² . Table 1 summarizes the open-circuit voltage and the spectral sensitivity current.

(Comparative Example 1)
According to FIG. 2, a multi-junction thin film silicon-based photoelectric conversion device as Comparative Example 1 was produced. In the same manner as in Example 1, a silicon-based photoelectric conversion device including the amorphous silicon photoelectric conversion unit 3, the intermediate layer 4, the crystalline silicon photoelectric conversion unit 5, and the back electrode 6 was formed.
When the photoelectric conversion unit having a 1 cm square light receiving area was separated from the silicon-based thin film photoelectric conversion device obtained as described above, the spectral sensitivity characteristic was measured, and the spectral sensitivity current was calculated from the sensitivity spectrum. / Cm ² . Table 1 summarizes the open-circuit voltage and the spectral sensitivity current.

Cross-sectional view of the structure of a multi-junction photoelectric conversion device according to the present invention Cross-sectional view of structure of multi-junction photoelectric conversion device in comparative example Spectral sensitivity characteristics of multi-junction photoelectric conversion device in the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Transparent electrode layer 3 Front silicon type photoelectric conversion unit 4 Intermediate layer 5 Back silicon type photoelectric conversion unit 6 Intermediate layer 7 CIS type photoelectric conversion unit 8 Back surface electrode layer

Claims (11)

  A multi-junction thin-film photoelectric conversion device comprising a silicon-based and CIS-based thin film photoelectric conversion unit, wherein the silicon-based photoelectric conversion unit and the CIS-based thin film photoelectric conversion unit are connected in series via an intermediate layer.   The multi-junction thin film photoelectric conversion unit according to claim 1, wherein the silicon-based thin film photoelectric conversion unit is composed of one or more members selected from the group consisting of amorphous silicon, amorphous silicon germane, and microcrystalline silicon. apparatus.   The multi-junction thin-film photoelectric conversion device according to claim 1, wherein the CIS-based thin film photoelectric conversion unit is formed from CIS-based nanoparticles.   The CIS-based thin film photoelectric conversion unit has a buffer layer, and the buffer layer is composed of at least one of the group consisting of ZnO, ZnS, and CdS. Multi-junction thin film photoelectric conversion device.   The multi-junction thin film according to any one of claims 1 to 4, wherein the intermediate layer includes at least one layer laminated in the order of transparent oxide layer / carbon layer / transparent oxide layer. Photoelectric conversion device.   6. The multi-junction thin film photoelectric conversion device according to claim 5, wherein the transparent oxide layer constituting the intermediate layer is made of zinc oxide.   The multi-junction thin film according to any one of claims 1 to 6, wherein an intermediate layer provided between the silicon-based thin film photoelectric conversion unit and the CIS-based thin film photoelectric conversion unit is formed of zinc oxide. Photoelectric conversion device.   The multi-junction thin film photoelectric conversion device according to any one of claims 1 to 7, wherein the film thickness of the intermediate layer is 10 to 2000 mm.   The multi-junction thin-film photoelectric conversion device according to claim 5, wherein the transparent oxide layer constituting the intermediate layer is formed of conductive oxygenated silicon.   A back electrode is provided on the side opposite to the light incident side of the multi-junction thin film photoelectric conversion device, and the transparent oxide semiconductor layer used for the back electrode layer is one of the group consisting of boron, aluminum, and germanium. The multi-junction thin film photoelectric conversion device according to any one of claims 1 to 9, wherein the above elements are doped.   The method for producing a multi-junction thin-film photoelectric conversion device according to any one of claims 1 to 9, wherein the CIS-based thin-film photoelectric conversion unit is manufactured in a temperature range of 200 degrees or less.

Images